general relativity of Einstein checked near our supermassive black hole

The theory of Einstein's general relativity is more than a century old. Much more than its discoverer, it testifies to the mysterious capacity of the human mind to anticipate the structure of reality, far from the everyday world that has accompanied the evolution of Homo's brain, based on mathematics that we do not find there. Any confirmation of the predictions of the Elle brings, however, a new conception of space and time, in which gravitation becomes a geometric property of … "data-url =" / sciences / definitions / physics-relativity-general -3572 / "data-more =" Read more "> General Relativity can be seen as a triumph, but also as a disaster because we are anxiously waiting to survey and understand new deeper and broader aspects This would be possible if the theory of "Science without religion is lame; religion without … "data-image =" https://www.cdn.v5.futura-sciences.com/buildsv6/images/midioriginal/7/0/a/70a355b0b6_50142362_einstein-1000.jpg "data-url = "/ sciences / personalities / physics-albert-einstein-205 /" data-more = "Read more"> Einstein showed his limits

Sagittarius A *, the black hole supermbadive laboratory [19659004AsplannedforthemonthofMay2018oneofthemostfamousstarsintheorbitofastronomy
In astronomy, the orbit designates the closed trajectory followed by a celestial body around another celestial body of periodically, under the influence of … "data-image =" https://fr.cdn.v5.futura-sciences.com/buildsv6/images/midioriginal/9/2/e/92eefd02ac_49145_iss-terre- sun-nasa-s-marshall-space-flight-center-flickr-cc-nc-20.jpg "data-more =" / sciences / definitions / universe-orbit-873 / "data-more =" Read more " > orbit around the central black hole of the From the Earth, we can not observe r a cross section … "data-image =" https://fr.cdn.v5.futura-sciences.com/buildsv6/images/midioriginal/7/7/7/777b761907_120668_voie-lactee-galaxie.jpg "data-url =" / sciences / definitions / universe-lane-way-3729 / "data-more =" Read more "> Milky Way found itself in the periastrophe, that's to the nearest point of Sgr A * on this orbit. Called S2, it was only about 16 light-hours, 120 times the distance between Earth and Sun or four times the distance Sun-Neptune from where the supermbadive black holes are?
They are carpeted in the heart of the majority of the great … "data-image =" https://www.cdn.v5.futura-sciences.com/buildsv6/images/midioriginal/a/1/4/a1479ad150_50038872_trou-noir-riazuelo-iap- 03.jpg "data-url =" / sciences / definitions / astronomy-black-hole-supermbadive-12722 / "data-more =" Read more "> black hole supermbadive four million L ' unit of mbad: the kilogram
The mbad is represented by the symbol m and, in … "data-image =" https://fr.cdn.v5.futura-sciences.com/buildsv6/images/ midioriginal / 8/4 / b / 84b0382c5e_80528_mbade.jpg "data-url =" / sciences / definitions / physics-mbad-15213 / "data-more =" Read more "> mbades solar that the it is thought to be towards the center of our Galaxie . This also corresponds to a distance equivalent to almost 1,500 Schwarzschild radii from this black hole. S2 is found at this periachron every 16 years and at that time, it traveled a portion of its elliptical orbit to almost 2.7% of the speed of light or 8.000 km / s. 19659005] Relativistic astrophysicists were anxiously awaiting this event because, as Futura explained in a previous article (see below), one could expect effects from the gravitational field of the black hole Sagittarius A * that are not described by Newton's theory of gravitation, and perhaps not even completely by Einstein's theory, opening a window to a new physics.

How the star S2 brought a new confirmation of the theory of general relativity. For a fairly faithful French translation, click on the white rectangle at the bottom right. English subtitles should then appear. Then click on the nut to the right of the rectangle, then on "Subtitles" and finally on "Translate automatically". Choose "French". © European Southern Observatory (ESO)

The opportunity to probe the gravitational field of a black hole in a regime, where it is intense, could not be missed. That is why many researchers and engineers had seized it as part of the Gravity consortium led by the Max Institute Planck for extraterrestrial physics (MPE) and involving the CNRS, the Paris Observatory – PSL, Grenoble-Alpes University and several other French universities (as well as the University of Cologne and the Portuguese Center for Astrophysics and Gravitation). The principle consists in the study of the interferences produced by the combination of coherent beams (coming from the same source and vibrating in phase) presenting a difference of step. It allows to obtain a better spatial resolution. "Data-url =" / sciences / definitions / physics-interferometry-2513 / "data-more =" Read the definition "> interferometry observations in the infrared made by several of the telescopes of Very Large Telescope (In 1993, the ESO launches the VLT project (Very Large Telescope) and decides to install it on the site of Cerro Parbad in the Chilean Andes, where the climate is particularly favorable for astronomical observations … "data-image =" https://fr.cdn.v5.futura-sciences.com/buildsv6/images/midioriginal/e/ 0/7 / f073110cb2_50034377_vlt.jpg "data-more =" / sciences / definitions / universe-vlt-2147 / "data-more =" Read more "> VLT ) of the ESO to make the equivalent of a telescope of more than 100 meters in diameter, while badyzing the white light
The wavelengths of visible light range from approx. iron 380 nm (violet) at 780 nm (red). The visible spectrum is … "data-image =" https://www.cdn.v5.futura-sciences.com/buildsv6/images/midioriginal/b/6/9/b697a0c09f_85912_lumiere.jpg "data-url =" / sciences / definitions / physics-lumiere-326 / "data-more =" Read more "> light using three instruments, Naco, Sinfoni, and Gravity The challenge was to be able to observe and measure the hour-by-hour movements of S2, with an accuracy of 50 microseconds angle, which is tantamount to watching a tennis ball posed on the A moon with a tiny "L" is the satellite of a planet. Phobos and Deimos are the two moons of the planet Mars.
The Moon
The Moon with a capital "L" is the only natural satellite of the Earth, it probably results from a collision there are 4 , 4 … "data-image =" https://www.cdn.v5.futura-sciences.com/buildsv6/images/midioriginal/c/7/8/c785911d64_50034415_lune-05.jpg "data-url =" / sciences / definitions / universe-moon-2550 / "data-more =" Read the more "> Moon from the Earth's Structure …" data-image = "https://www.cdn.v5.futura-sciences.com/buildsv6/images/midioriginal/8/4/ f / 84ff7edce5_123534_terre-apollo8.jpg "data-url =" / planet / definitions / structure-earth-earth-4725 / "data-more =" Read more "> Earth .

The first measurement of the spectral shift effect of a black hole

The ESO has just announced today, via a press conference that accompanies the setting on line on arXiv an article explaining the scientific results, that a culmination of 26 years of star observations around Sgr A * with its telescopes had been achieved. In fact, the theory of general relativity implies that the gravitational field of a star produces a shift towards the red of light that it can emit, all the more important as it is mbadive or dense, and this, according to a precise law

This is indeed what has been observed with S2, and just as it was the case a century ago with the deviation of the light rays of stars by the Sun. closest star to the Earth, from which it is distant about 150 million kilometers. The Sun is located at 8.5 kparsecs from the center of the Milky Way. In the clbadification of stars, the sun is a star of type G2.
The mbad … "data-image =" https://fr.cdn.v5.futura-sciences.com/buildsv6/images/midioriginal /1/d/9/1d9cd1d45f_50034577_eruption.jpg "data-more =" / sciences / definitions / universe-sun-3727 / "data-more =" Read more "> Sun observed and measured during the famous eclipse of 1919, the measured effects can not be explained with Newton's theory of gravitation, but on the contrary are in full agreement with the accuracy of the measurements reached with Einstein's theory.

C ' is the first time this shift effect is measured for the gravitational field of a black hole, previously known, especially with white dwarfs (the first solid detection dates back to 1954 with 40 Eridani B), and could be measured in the much weaker field of the Earth via the famous experiment of Pound and Rebka.

This new success of the theory of general relativity should soon be followed by another, very likely. Indeed, the observations in progress should make it possible to observe the relativistic component of the precession of the periastrome of S2, the equivalent of the famous relativistic precession of the perihelion of Chemistry: mercury, a chemical element [19459011MercuryistheadjoiningelementofgoldintheperiodictableoftheelementsandoneofthefavoritesofthealchemistsIthastheparticularityofbeingtheonlymetal"data-image="https://encdnv5futura-sciencescom/buildsv6/images/midioriginal/e/d/e/edf75f57d9_82666_mercureokjpg"data-url="/sciences/definitions/astronomy-mercury-3722/"data-more="Readmore"> Mercury 16 years ago, although we did not have of instruments as powerful as today, a previous pbadage to the periastrophe of S2 had been observed, thus allowing a comparison in progress with that of 2018.

What to remember

• The theory of relativity general predicts a red spectral shift effect for a light source in a gravitational field.
• The effect was known in the laboratory on Earth but also with white dwarfs. It allows to observe differences between the prediction of Einstein's theory and that of Newton, especially since the field of gravity is strong.
• The observation of the transition to the the star S2 orbiting the supermbadive black hole of the Milky Way with instruments equipping the VLT in Chile (especially the one called Gravity) showed such a shift.
• This is the first observation of this effect in the field of gravitation of a black hole and also a new test succeeded by the theory of the general relativity.

Gravity, pointed at the galactic black hole, ready to check the general relativity

Article of Xavier Demeersman published the 25/06/2016

With its supermbadive black hole of four million solar mbades, the center of the galaxy is, for astrophysicists, the ideal laboratory to test the theory of general relativity. Einstein. The new Gravity VLT instrument, designed to auscultate it, did not disappoint: it has just offered its first observations of a star moving close to Sagittarius A *, the center of our galactic world. In 2018, it will be so close that the relativistic effects will be directly detectable.

In the summer of 2015, ten years after the launch of the project, an international team of astronomers and engineers installed Gravity instrument in tunnels under one of the largest observatories in the world, the VLT ( Very Large Telescope ), at the top of Mount Parbad in Chile. Working in interferometry, this optoelectronic system combines the light of four 1.8-meter auxiliary telescopes of the VLT ( Auxiliary Telescopes or AT) to create a virtual mirror 130 meters in diameter with the Very Large Telescope Interferometer (VLTI), which brings a much larger resolution.

The instrument completed its first observation campaign in January 2016. ] "Gravity will allow to extend the optical interferometry to the observation of much less luminous objects, and will push well beyond the current limits the sensitivity of the astronomy with high angular resolution" then commented the director of operations, Franck Eisenhauer, Max Planck Institute.

Now the preliminaries are coming to an end and the tests performed with the instrument mated to the four giants, the units of 8.2 meters in diameter. to be each one ( Unit Telescopes or UT), are very promising, just announced the ESO, the European Observatory Austral. In comparison with the observations of only one of these units, the gains in resolution and accuracy on the position of an object are of a factor of 15. It will soon reach, for example, centimeter accuracy for an object located on the Moon.

Gravity proof theory of general relativity

The main objective of Gravity is the study of the intense gravitational field of black holes, and more particularly that of Sagittarius A * with 4 million solar mbades, belongs to the category of supermbadives. Invisible, they are betrayed by the dances of stars trapped around them. It is in this way that the position and mbad of Sgr A *, lurking in the heart of our Galaxy, about 25,000 light-years from the Earth, could be inferred in 2002. [19659005] Also, by tracking with as much precision as possible the movement of the stars that surround it, the researchers intend to learn more (rotation rate, mbad, electric charge) on this dark body. Above all, as the name of the project indicates, they will be able to compare the measurements to the predictions of theory of general relativity of Albert Einstein. Indeed, for physicists, the center of the Milky Way constitutes an ideal laboratory, in accordance with their expectations.

The piercing view of the instrument (10 microseconds of angle to determine the position of the objects, and a resolution of four milliseconds of angle to image the objects) recently made it possible to follow the star S2, a very close neighbor of Sgr A *, who turns around him in sixteen years. "When the light from the star for the first time interfered, the team had a fantastic time, crowning eight years of hard work says Franck Eisenhauer. At first, we stabilized the wave phenomenon due to … "data-url =" / sciences / definitions / physics-interference-1012 / "data-more =" Read more "> [19459007Interference on a near bright star.A few minutes later, we were able to observe the interference generated by the weak star brightness . " A feat of which they are very proud

Critical observations in 2018

The first results of Gravity, a very complex instrument to implement, are therefore very encouraging, so much the better, because in 2018, the star S2, which travels at 2.5% of the speed of light (30 million km / h), will reach the point of its orbit nearest supermbadive black hole . It will be distant only 18 billion kilometers, about 17 light hours, or four times the distance between Neptune and the Sun. The gravitational effects will be strongly felt, which promises crucial observations.

For the first time, says the ESO, the team will be able to measure two relativistic effects caused by the rotation of a star around a black hole: the gravitational redshift resulting from the loss of energy that the light of the star undergoes when it escapes from the intense gravitational field of the black hole , and the precession of the pericenter, an effect observed on a smaller scale with the orbit of Mercury around the Sun (with an intensity however 6.500 times lower than near the galactic black hole).

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